Contact sockets and manufacturing method

ABSTRACT

Contact socket comprises four parallel contact arms arranged in surrounding relationship to the socket axis. Cylindrical spring surrounds the arms and, upon insertion of a contact pin, resiliently urges them against the surface of the pin. Inner ends of arms are integral with a sheet metal strip from which they were formed. A strip of sockets is manufactured by blanking a stock metal strip to produce arms on each side, these arms being later twisted and bent to produce any one of several types of socket strip including single or double rows of sockets on parallel spaced-apart axes and axially aligned contact sockets on opposite sides of the strip.

United States Patent [72] Inventor Clarence Leonard Paullus Camp Hill, Pa.

[21 Appl. No. 801.436

[22] Filed Feb. 24. 1969 [45] Patented Sept. 14. 1971 [73] Assignee AMP Incorporated Harrisburg, Pa.

[54] CONTACT SOCKETS AND MANUFACTURING METHOD 23 Claims, 14 Drawing Figs.

[52] U.S. Cl 339/259, 339/262 [51] Int. Cl l-l0lr 13/16 [50] Field of Search 339/19,

FOREIGN PATENTS 286,966 3/1928 Great Britain 339/259 6,505 l 36 7/1966 Netherlands 339/258 Primary E.raminer-Marvin A. Champion Assistant Examiner-Joseph H. McGlynn Attorneys-Curtis Morris, Marshall M. Safford, William Hintze Holcombe, William J. Keating, Frederick W. Raring, John R. Hopkins. Adrian J. La Rue and Jay L. Seitchik ABSTRACT: Contact socket comprises four parallel contact arms arranged in surrounding relationship to the socket axis. Cylindrical spring surrounds the arms and, upon insertion of a contact pin, resiliently urges them against the surface of the pin. Inner ends of arms are integral with a sheet metal strip from which they were formed. A strip of sockets is manufactured by blanking a stock metal strip to produce arms on each side, these arms being later twisted and bent to produce any one of several types of socket strip including single or double rows of sockets on parallel spaced-apart axes and axially aligned contact sockets on opposite sides of the strip.

PATENTEU SEP 1 4 law SHEET 1 [1F 6 PATENIED SEP] 4 l97| SHEEI 2 OF 6 PATENIED SEPI 4 I97! SHEET 3 [IF 6 PATENTED SEN 4B7! SHEET 5 OF 6 CONTACT SOCKETS AND MANUFACTURING METHOD BACKGROUND OF THE INVENTION This invention relates to contact sockets of the type adapted to receive an electrical pin or other male member. The herein disclosed embodiments of the invention are particularly intendeu for use in a terminal junction system and will be described with reference to terminal junction systems and the particular problems and conditions encountered in such systems, however, it will be apparent that sockets in accordance with the invention can be used in many other environments such as conventional multicontact connectors and headers of the type used on electrical devices.

The term terminal junction system is commonly understood to refer to an interconnecting means for wires comprising a plurality of modulesmounted in a suitable frame, each module being adapted to receive contact pins secured to the ends of wires. Contact sockets are contained in the modules and are electrically connected to each other so that two or more wires can be electrically connected by inserting the contact pins on their ends into the sockets contained in the modules. It is now common practice to provide eight or contact sockets in each module and to manufacture-the modules with many different arrangements as regards commonly connected sockets in the modules; for example, a module containing 10 contact sockets might have all of the sockets electrically commoned with each other so that all of the contact pins inserted into'the module would be commonly connected. Alternatively, the module might contain two groups of commonly connected sockets, one group comprising six sockets and the other group comprising four sockets so that six conductors could be commonly connected in one section of the module and four conductors could be commonly connected in another section of the module.

Terminal junction systems can be made extremely compact in the sense that a large number of interconnections can be made in a small space and for this reason, among others, they are presently being designed into aircraft and other installations where space and weight must be conserved. However, terminal junction systems can be used to advantage under many circumstances where other types of interconnecting devices are now used such as terminal blocks having screwtype terminals thereon.

The present invention is directed to the achievement of an improved contact socket which is extremely compact and light in weight, relative to its current-carrying capabilities, which can have its conductive parts formed of pure copper, which provides a stable, low-resistance electrical connection with an inserted pin, and which can be manufactured as a member of a cluster or group of sockets in any one of several forms as regards the positions of the sockets in the cluster with respect to each other. It is also among the objects of the invention to provide an improved and efficient manufacturing method for contact sockets which permits the achievement of the objects mentioned immediately above with a minimum of metal stock and scrap losses.

These and other objects of the invention are achieved in a preferred embodiment thereof comprising a contact socket having four contact arms, the intermediate portions of the arms extending parallel to each other and being arranged, relative to the socket axis, at evenly spaced angular intervals around the axis. A split cylindrical spring surrounds the arms and resiliently urges them into engagement with an inserted contact pin, the spring being independent of the contact arms so that the arms and other parts of the socket or strip can for formed of a highly conductive metal, such as pure copper, rather than from a material having good spring properties. The inner ends of the arms are integral with, and extend from, a continuous metal strip which functions as a bus bar and which extends to the other socket or sockets of the group. The arms are twisted about their own longitudinal axes adjacent to their fixed ends to achieve the circular arrangement of arms around the socket axis. Depending upon the precise form of the arms, the manner in which the arms are formed and twisted, and depending upon the precise form of the plate section or bus bar, sockets in accordance with the invention can be provided as individuals, as aligned sockets on opposite sides of a bus bar, or can be provided as continuous rows of aligned sockets on parallel spaced-apart axes. In the drawings:

FIG. 1 is a fragmentary perspective view of a portion of a terminal junction system showing one of the modules exploded from the frame.

FIG. 1A is a perspective view of a typical contact pin of the type used in terminal junction systems.

FIG. 2 is a perspective view of a short section of contact socket strip in accordance with one embodiment of the invention.

FIG. 3 is a perspective view of a strip of blanks adapted to be formed to produce the socket strip of FIG. 2.

FIG. 3A is a perspective view of an alternative form of blank.

FIG. 4 is a longitudinal sectional side view of a module containing contact sockets in accordance with the embodiments of FIGS. 2 and 7 of the invention.

. FIGS. 5 and 6 are views taken along the lines 5-5 and 6-6 ofFIG.4.

FIG. 7 is a fragmentary sectional side view of the module of FIG. 4 showing details of the contact receiving cavities therein. FIG. 8 is a perspective view of a section of socket strip in ac- TERMINAL JUNCTION SYSTEMS IN GENERAL Referring first to FIG. 1, a typical terminal junction system comprises a plurality of identical modules 2 mounted in a frame 4 which may consist of a channel-shaped member having a web 6 and sidewalls 8, 10, the modules 2 being adapted to be mounted between the sidewalls of the frame. Suitable clamping means (not specifically shown) are provided at each end of the stack of modules to secure them in the frame and interlocking means 12 may be provided on the sides of the individual modules, as fully disclosed in US. Pat. (application Ser. No. 640,649), to prevent accidental removal of a central module from the stack. The individual modules 2 contain two parallel rows of five openings on their upper sides, each opening being adapted to receive a contact pin 14, FIG. 1A, having a generally cylindrical contact tip 16, a radially extending collar l8, and a rearward end 20 which is crimped or otherwise secured to the end of a wire 22.

Referring to FIGS. 4-7 the individual modules 2 each comprise a body portion or housing 24 of epoxy resin or other suitable moldable material, having cavities 26 extending from their upper sides 28 to their lower sides 30. Each cavity has an entrance portion 32 adjacent to the upper side which communicates with an enlarged cylindrical chamber 34 which in turn communicates with a constricted neck portion 36, the diameter of which is slightly greater than the diameter of the contact tip section 16 of the pin 14. A retaining member, which is structurally separate from the socket strip, is mounted in chamber 34 to retain an inserted contact pin in the module. The cavity constriction 36 opens into a relatively short large diameter section 38 which in turn extends into a rectangular recess 44 in the lower side 30 of the block. Barrier walls 40, 42 project partially into this open lower side 44 between adjacent cavities and serve to separate groups or clusters of contact sockets as will be explained below. As will also be explained these barriers are at least partially removed when the socket clusters are mounted in the housings.

The bottom of the housing 24 is closed and sealed by a suitable base plate 46 which is bonded to the lower surface of the housing and which has two rows of square bosses 48 on its upper surface disposed in alignment with the cavities in the housing. Each boss 48 has a recess or depression 49 on its upper surface which is adapted to receive a projecting tab of the type of socket strip shown in FIG. 8.

A sealing block 50 of relatively soft compressible material such as a silicone rubber is bonded to the upper side of the housing 24 and fits within a rectangular recess 56 on the upper side. Sealing block 50 has openings 52 extending therethrough in alignment with the cavities 26 in the block 24, these openings being constricted along at least part of their lengths as shown at 54 so that after a terminal and wire are forced through an individual opening, the partially compressed sidewalls adjacent to the opening will bear against the wire as shown in FIGS. 4 and 5 to seal the cavity and the inserted contact pin from the atmosphere.

Modules of the type shown at 2 are adapted to receive either terminal socket strip of the type shown in FIG. 2 or of the type shown in FIG. 8. As will become apparent as this description proceeds, the contact sockets of the embodiments of FIGS. 2, 8, are similar to each other in many respects although there are significant differences between the three types of strip shown in these figures.

THE EMBODIMENT OF FIG. 2

The contact sockets 62 of the embodiment of FIG. 2 comprise four contact arms generally indicated at 64, 66, 68, and 70 which are arranged at equally spaced angular intervals around the socket axis. The intermediate portion 72 of each arm which extends from a location adjacent to the free end 74 to a twisted area 76, has an arcuate cross section which is inwardly concave toward the socket axis and which has a radius substantially equal to the radius of the contact portion 16 of the contact pin. The tip portion 74 of each arm 72 is outwardly directed to provide a lead-in surface for the contact pin during insertion. The twisted portion 76 at the lower end (as viewed in FIG. 2), of the intermediate portion 72 constitutes a transition zone which joins intermediate portions 72 to an obliquely extending base section 78. This base section is reversely bent at its lower end 80 and it is integral with a continuous metal strip 82 from which it was formed. The portions 83 of this strip which lie immediately beneath the associated sets of arms 64-70 function as the inner ends of the individual contact sockets while the portions 88 of the strip which extend between adjacent contact sockets function as bus sections for carrying current from one socket to the other sockets of the strip.

The intermediate portions 72 of the arms of each socket are surrounded by a cylindrical spring 84 having a open spiral seam 86, this spring functioning to protect the contact arms and to resiliently urge their inner surfaces against the surface of an inserted pin as shown in FIG. 4.

The socket strip comprising the central bus strip 82 and the arms of the individual contact sockets can be of any conductive metal although pure copper is the most desirable metal to use because of its excellent electrical conductivity, the ease with which it can be formed, and (for aircraft uses) the fact that it is nonmagnetic. It will be recalled that unalloyed copper has very inferior spring properties and for this reason it is usually not used for contact terminal members having an integral spring for establishing contact force. In the contact sockets of the instant invention however, the spring 84 is manufactured separately from the contact arms and bus strip and can be of a material having optimum spring characteristics although it need not have good electrical conductivity. Stainless steel, for example, is ideally suited as a material for the spring 84 because its spring properties are adequate and in addition it is electrolytically passive so that it will not cause corrosion of the contact arms. It should be added that a socket assembly in accordance with the invention will be completely nonmagnetic if a nonmagnetic stainless steel is used for the spring.

FIG. 3 shows a blanked and partially formed strip of sheet metal and illustrates some of the manufacturing steps for producing the socket strip of FIG. 2. In this figure, the strip is shown as having associated pairs of arms 64', 66', 68', and 70' extending from its opposite edges. The arms do not extend precisely parallel to each, other but their outer portions, beginning at the twist line indicated at 71, are directed slightly inwardly and towards each other. It will be understood that the arms are blanked from a wide strip of stock metal in this inwardly directed form and that in this embodiment, the arms of the pairs 64', 66', and 68', 70, were not bent inwardly after blanking.

After the arms 64'70 have been blanked from the stock metal, the intermediate portions 72 of the arms are formed to produce the concavities and the free end portions of the arms are bent downwardly as shown at 74. Thereafter, the arms are twisted about their longitudinal axes generally along the imaginary lines indicated at 71 so that their concave upper surfaces, as viewed in FIG. 3, face obliquely upwardly in crossing directions; in other words, the arms are twisted towards each other.

In the final manufacturing steps of the socket strip of FIG. 2, the fixed end portions of the arms are bent upwardly as indicated at 80 in FIG. 2 until the intermediate sections 72' extend parallel to each other in surrounding relationship to the socket axis. It will be understood that where the manufacturing procedure of FIG. 3 is followed, it is only necessary to bend the base sections or fixed ends of the arms upwardly through a right angle to locate the intermediate portions of the arms 72 in a circular array as shown in FIG. 2 because of the initial form of the arms, that is, because of the fact the outer end portions of the arms extend obliquely towards each other to some extent.

When the arms are bent upwardly, they can be overformed, that is, bent inwardly beyond their normal positions, to permit the spring members 84 to be moved downwardly in surrounding relationship with the intermediate arm portions 72. The final finishing operation then comprises the insertion ofa sizing pin, having a diameter equal to the contact portion of the contact socket, into the socket to set the arms at the desired diameter as shown by the two sockets on the right in FIG. 2.

The invention presents many advantages, from a manufacturing standpoint, which become apparent from a consideration of FIG. 3 and the manufacturing steps disclosed therein. For example, sockets in accordance with the invention can be manufactured with a minimum of material waste since the width of the strip stock required extends from the tips of the arms 64, 66', to the tips of the arms 68', 70. Furthermore, the spacing indicated at d" in FIG. 3 between the two arms of each associated arm pair is substantially equal to or even less than, the diameter (1" of the contact pin for which the contact socket is designed. Thus, the only material lost as scrap when the strip of FIG. 3 is blanked from stock material, is the stock metal removed from between adjacent arms of each pair, such as the arms 64', 66', and the material removed from between adjacent pairs of arms on each side of the central strip 82. It should also be noted, that the spacing s between adjacent pairs of arms along the length of the central strip 82 is not critical and can be as small as desired. In the instant embodiments of the invention, this spacing s" is determined not by manufacturing considerations of the strip itself but rather by the thickness of the walls of housing 24 between adjacent cavities. It follows that under some circumstances, this spacing .r" might be substantially less than that shown in the blank of FIG. 3.

The fact that the contact strip can be of pure copper, rather than spn'ng material, gives rise to a further manufacturing advantage in that pure copper is easily stamped and fonned with lOlOOI I 02l9 very little wear on the forming tooling. Furthermore, no heat treatment of the strip, subsequent to blanking, is required.

FIG. 3A shows an alternative form of blank in which the arms 64", 66", 68", 70" extend normally from the central strip 82". These arms thus differ from the arms of FIG. 3 in that the arms of FIG. 3 are directed inwardly and towards each other at their ends. When the blank of FIG. 3A is formed to prod..-e the socket 62, the individual arms are twisted about their longitudinal axes along twist lines 71", these twist lines extending normally of the sides of the arms rather than obliquely as in FIG. 3. In order to position the intermediate portions of the arms at the proper location with respects to the socket axes, the base portions 83" of the arms are formed into a generally conical surface when the arms are bent upwardly. This alternative manufacturing method is mentioned at this time because of the fact that subsequent embodiments of this invention described hereinbelow are shown as being formed from a blank of the general type shown in FIG. 3A rather than from a blank of the general type shown in FIG. 3. Furthermore, depending upon the thickness of the material, the spacing between adjacent pairs of arms on the strip, and possibly other considerations, one or the other methods of FIGS. 3 and 3A may prove preferable from a manufacturing standpoint.

Contact socket strip of the type shown in FIG. 2 can be produced in any desired length having any desired number of sockets thereon. In FIG. 4, on the left, a strip of three sockets 62a, 62b, 62c is shown as being mounted in the left-hand section of the module. The strip can be assembled to the module by merely moving the section of three sockets upwardly prior to positioning the base-plate 46 on the housing and locating the sockets in three adjacent aligned cavities. When the base plate 46 is cemented to the lower end of the housing 24, the upper surfaces of the bosses 48 will support the underside of the carrier strip 82 as shown. It will be noted that the lower portions of the barriers 40 between the cavities in which the sockets 62 a, 62b, 620 are disposed have been removed as indicated at 90. This can be done at the time of molding, or the lower portions can be physically removed when the housing is assembled with the contact strip. The two cavities shown on the right in FIG. 4 contain a different type of socket strip as will be explained below.

As previously noted, the contact pins are engaged with the sockets by merely moving them downwardly through the ceiling block 50 until the lower ends of the pins extend through the constrictions 36 of the cavities and into the sockets. When a pin is inserted, its collar moves past a retaining member 58 in the cavity portion 34. This retaining member is in the form of a hallow cylinder having inwardly and downwardly directed lances 60 on its opposite sides which are adapted to engage behind the rearwardly facing shoulder formed by the collar 18 of the pin to prevent accidental removal of the pin from the contact socket. Intentional removal of an individual contact pin from the module can be achieved by means of a tool which is movable through the sealing block 50 and along the wire to bias the retainer lances 60 outwardly.

THE EMBODIMENT OF FIG. 8

FIG. 8 shows an alternative embodiment comprising a composite strip 92 having contact sockets 93 arranged in two parallel rows. Each contact socket comprises four contact arms 98, 100, 108, 110 which are surrounded by a cylindrical spring 84 of the type previously described. The sockets themselves are similar, if not identical, to the sockets 62 of FIG. 2 but the base strip 92 from which the socket arms extend is of a form different from the base strip of the previously described embodiment as will be apparent from the description set forth below.

The strip 92 is comprised of first and second separate strips 94, 96 (FIG. 9), the strip 96 being centrally positioned on the upper surface of the strip 94 and secured thereto. The first strip 94 is relatively wide, having a width indicated at 2d in FIG. 9 which is substantially equal to an slightly greater than two times the diameter d of the contact pin. Contact arms 98, 100, 102, 104 extend upwardly from the opposite edges of strip 94, the arm 98 being in alignment with arm 102 and the arm being in alignment with the arm 104. The arms are integral with edges of the strip and face inwardly and towards each other. The strip may be manufactured as generally described above with reference to FIG. 3 or 3A.

The second strip 96 of the composite strip 92 is relatively narrow and has arms 108, extending from one edge thereof and arms 112, 114 extending from its other edge. Again, the lower ends of the arms are integral with the strip in the manner described above and may be manufactured as previously described. The arms 108-114 are twisted but in this instance, the twists are imparted to the arms in a manner such that the concave faces of the intermediate contact portions are directed outwardly from the strip 96 and obliquely rather than inwardly (as on the strip 94). The central strip 96 has lateral extensions 116 between each associated pair of arms and the ends 118 of these extensions are directed downwardly and adapted to be inserted through openings 106 in the lower strip 94. In order to secure the two strips 96, 94, to each other, the projecting lower ends of these downwardly directed flanges 118 can be upset or spread by splitting as indicated at 105, FIG. 4. Other methods of securing the strips together could be used, for example, soldering or welding.

When the two strips, 94, 96 are assembled to each other, the locations of the arms on the strips are thus such that the arms 108, 110 of the strip 96 cooperate with the arms 98, 100, to form a contact socket on one side of the composite strip. Similarly, the arms 112, 114 of the strip 96 are opposed to and cooperate with the arms 102, 104 of the lower strip 94 to constitute a contact socket on the opposite side of the strip. The resulting composite strip thus has two side-by-side rows of sockets commonly connected to each other with the two sockets in each row in side-by-side relationship.

The right-hand portion of the module shown in FIG. 4 and the portions of the module shown in FIG. 5 show a cluster of four contact sockets, three sockets being indicated at 93a, 93b, 93c mounted in the module. Four contact pins inserted into these modules would thus be commonly connected. It will be noted that the lower portions of the barrier 42 in FIG. 5 has been removed as indicated at to permit the central portion of the composite strip to pass beneath this barrier and that the projections 118 on the underside of the strip extend into the recesses 49 of the bosses 48. It will be apparent that in the module shown, up to ten electrically common contact sockets can be mounted if the appropriate barriers 40, 42 are removed. The strip shown in FIG. 8 can thus be cut to the appropriate length to provide any desired number of electrically common sockets.

A significant feature of the embodiment of these inventions as shown in FIG. 8 is that two separate electrical paths are provided between any two contact sockets of the strip by reason of the fact that each socket contains two contact arms from one of the strips 94, 96, and two contact arms from the other strip. To illustrate in FIG. 5 it is apparent that the contact pin on the right is in engagement with the contact arm 100 which is integral with the lower strip 94. The contact arm on the left is in electrical contact with the arm 104 which is also integral with the lower strip 94. These arms 100, 104 and the strip 94 provide the first contact path between the two terminals. The terminal on the right is also in electrical contact with the contact arm 110 of the strip 96 while the arm on the left is in electrical contact with arm 1 14 which is also integral with the strip 96. These arms thus provide the second contact path between the two terminals shown. Terminal strip of FIG. 8 and 9 thus provides not only redundant contacts between each socket and its inserted pin (by virtue of the four contact arms) but also provides redundant circuit paths between any one inserted terminal of the strip and any other terminal inserted into a contact of the strip. This double redundancy of the strip represents a substantial contribution to overall reliability. It will be apparent that this dual circuit path feature of the invention does not require four arms for each socket but could be achieved with a socket having a total of only two arms which would be wider than the arms shown.

THE EMBODIMENT OF FIGURE 10 FIGS. 10 and 11 show a further embodiment of the invention in which axially aligned contact sockets 122, 123 extend from the edges a composite strip 124. The strip 124 is comprised of first and second identical strips 126, 128, strip 126 having aligned pairs of arms 130, 132 and 134, 136 extending from its longitudinal edges and the strip 128 having arms 138, 140 and 142, 144 extending from its longitudinal edges. The arms of each pair are, like the arms of previously described embodiments, provided with intermediate contact portions having arcuate cross sections which are directed obliquely inwardly along crossed paths. This effect is again achieved by twisting intermediate portions of the arms when they are in the blank stage as explained with reference to FIG. 3. As illustrated at FIG. 11 with reference to the arm 130, a transition section 152 adjoins the twist immediately adjacent to the intermediate contact section, this transition section extending obliquely away from the plane defined by central strip 126. At the lower end of the arm 130, the transition section is reversely bent as shown at 150 to provide a base section 148 which in turn is rightwardly bent at 146 at its juncture with the central strip 126. The arm 132 is similar to the arm 130 although its transition section extends obliquely in the opposite direction from the transition section of the arm 132.

In general, the strips 126, 128 can be manufactured in accordance with the manufacturing principles explained with reference to FIG. 3 and the advantages of ease of forming, low scrap losses, will be achieved. The two strips are assembled to each other by means of laterally projecting ears 153 which extend from the central strips 126, 128 between the arms on one edge of the strips. It will be apparent that two strips, 126, 128 can be manufactured with the same tooling. The strips are secured to each other by positioning their opposed surfaces against each other, bending the projection 152 through a 180 angle and forming interlocking indentations 156 in the ears and the strips as indicated in FIG. 12 to hold the strips together. When the strips are locked together, the arms 138, 140 of the strip 128 and the arms 130, 132 of strip 126 will define one socket on the upper side of the composite strip as viewed in FIGS. 10 and 11. Similarly, the arms 142, 144, 134, and 136 will define the socket on the lower side of the composite strip. It will be noted in FIG. 10 that in this instance the inner ends of the sockets are defined by the portions 148 of the contact arms which extend normally from the edges of the contact strips 126, 128. Again, a cylindrical spring is assembled to each set or group of four arms to impose the contact pressure on the inserted pin.

Contact socket strip of the type shown in FIG. 10 is adapted to be used in terminal junction with the contact sockets 122, 123 on each side of the composite strip disposed in the adjoining socket cavities as shown. In the arrangement shown in FIG. 12, provision is made for commonly connecting ten conductors, five extending from the right and five from the left. It will be apparent, however, that the composite strip of FIG. 10 can be made in any desired length having any desired number of socket cavities thereon. modules of the type shown in FIG. 12. These modules, which are made up of two of the housing sections indicated at 24a, 2412 are adapted to receive contact pins on each side to form interconnections between conductors extending axially towards each other. The two housing sections 24a, 24b, without base plates 46 shown in FIG. 4, are bonded to each other along their sides so that their open lower ends 44 are in communication with each other. The open portions 44 thus define a chamber running the length of the housing in which the composite strip 124 can be located with the contact sockets 122, 123 on each side of the composite strip disposed in the adjoining socket cavities as shown. In the arrangement shown in FIG. 12, provision is made for commonly connecting ten conductors, five extending from the right and five from the left. It will be apparent, however, that the composite strip of FIG. 10 can be made in any desired length having any desired number of socket cavities thereon.

The embodiment of FIG. 10, like the embodiment of FIG. 8, provides two electrically separate conducting paths between each pair of aligned contact sockets by virtue of the fact that the strip is composed of two electrically separate strips 126, 128. Thus referring to FIG. 10, if contact pins are inserted into one of the upper sockets and one of the lower sockets, the contact arms 138, 140, the strip 128, and the contact arms 142, 144 will provide a first contact path between the pins. The contact arms 132, 130, 134, and 136, and the strip 126 will provide the second conducting path which is or can be electrically independent of the first path. Again, redundant paths provide a high degree of reliability in that the failure of either path does not interrupt the circuit between the two inser ed pins. As with the embodiment of FIG. 8, the redundant circuit paths could be achieved with a contact socket having only two arms rather than four.

The structural and manufacturing principles of the invention can be used in a wide variety of connecting devices other than terminal junction systems. By virtue of their structural features, contact sockets in accordance with the invention can most conveniently be manufactured in strip form by a series of blanking and forming operations but the sockets need not be used in strip form. For example, individual sockets can be mounted in headers of the type provided on components such as relays, motors etc. at the time of manufacture so that when the component is placed in a larger piece of equipment, the wiring of the equipment can be accomplished by means of wires having contact pins of the type shown in FIG. 1A on their ends. Additionally, contact sockets in accordance with the invention might be used in conventional pin and socket connectors in which case the base strips of the sockets could be replaced by cylindrical ferrules adapted to receive, and be crimped onto, a wire. The entire socket as disclosed can be enclosed in a tubular sleeve under these circumstances to protect the four arm socket from damage.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only.

I claim:

1. A stamped and formed electrical contact socket adapted to receive a contact pin, said socket comprising at least four contact arms arranged in parallel surrounding relationship to the axis of said socket, said arms having free ends and fixed ends, said free ends defining the entrance to said socket and said fixed ends defining the inner end of said socket,

said fixed ends being integral with, and extending from sheet metal strip means,

said arms having twisted portions at locations intermediate their ends, said arms being twisted, at said twisted portions, about their own longitudinal axes thereby to orient intermediate surface portions of said arms in facing relationship to said axis of said socket, said intermediate surface portions being adapted to be engaged by an inserted contact pin and to establish electrical contact therewith.

2. A contact socket as set forth in claim 1 including spring means in surrounding relationship to said arms for urging said arms against said inserted pin.

3. A contact socket as set forth in claim 1 wherein said strip means extends substantially normally of said axis of said socket, said arms extending from opposite sides of said strip means and being bent'adjacent to their fixed ends in a common direction.

4. A contact socket as set forth in claim 3 wherein said strip means extends laterally beyond said socket and including an additional socket identical to said socket, said additional lOIOOl 022l socket comprising arms integral with, and extending from, said strip means.

5. A contact socket as set forth in claim 3 wherein said arms extend obliquely from said twisted portions towards said strip means.

6. A contact socket as set forth in claim 1 wherein said strip means comprises first and second separate strips extending substantially normally of said axis of said socket, two of said arms extending from one side of said first strip and two of said arms extending from one side of said second strip, and including an additional contact socket having arms extending from the remaining sides of said first and second strips.

7. A contact socket as set forth in claim 6 wherein said second strip extends medially along said first strip.

8. A contact socket as set forth in claim 6 wherein said first and second strips are substantially identical and are disposed against each other in parallel planes, the axes of said sockets being parallel to the 9. Electrical connecting means comprising at least two contact socket means, each of said socket means being adapted to receive a contact pin, said connecting means comprising:

first and second stamped and formed bus sections, each of said bus sections comprising a flat strip of conductive metal, said strips being disposed against each other in parallel planes,

each of said contact socket means comprising first and second contact arm means, each said contact arm means having a free end and a fixed end, said fixed end of said first contact arm means of each of said contact socket means being integral with said first bus section and said fixed end of said second contact arm means of each of said contact socket means being integral with said second bus section,

said first contact arm means of said first bus section being opposed to said first contact ann means of said second bus section to define at least one said socket means, and said second contact arm means of said first bus section being opposed to said second contact arm means of said second bus section to define at least another one of said contact socket means.

10. Connecting means as set forth in claim 9 wherein said first and second contact arm means each comprises a pair of contact arms.

11. Connecting means as set forth in claim 9 comprising pairs of socket means in axial alignment with each other.

12. Connecting means as set forth in claim 11 wherein said first and second bus sections are of substantially equal width and are against each other in substantially coinciding relationship, said socket means extending in opposite directions from opposite edges of said bus sections.

13. Connecting means as set forth in claim 9 in which said socket means are axially offset from each other.

14. Connecting means as set forth in claim 13 wherein said socket means are disposed on parallel spaced-apart axes.

[5. Connecting means as set forth in claim 14 wherein said first bus section has a width which is substantially greater than the width of said second bus section, said second bus section being centrally disposed on said first bus section, said socket means extending from said bus sections in the same direction.

16v Connecting means as set forth in claim 9 wherein said first and second contact arm means each comprises a plurality of arms extending from said first and second bus sections respectively, said arms in each of said socket means being arranged in a circular array around the socket axis.

17. Connecting means as set forth in claim 16 including spring means in surrounding relationship to each of said pluralities of arms.

18. Electrical connecting means comprising a plurality of contact sockets disposed in single file, side-by-side, spacedapart, parallel relationship, said connecting means comprising:

an elongated bus strip of conductive metal,

each of said sockets comprising four contact arms, two of said arms being integral with, and extending from, one side of said bus strip and two of said arms being integral with, and extending from, the other side of said bus strip, said arms being in alignment with each other on opposite sides of said strip, each of said arms having a twisted portion intermediate its ends and being twisted, at said twisted portion, with respect to its own longitudinal axis thereby to orient an intermediate surface portion of each arm in facing relationship to the axis of said socket, said intermediate surface portion being adapted to be engaged by an inserted contact pin to establish electrical contact therewith, each of said arms extending from its twisted portion generally obliquely towards said bus strip, and

each of said sockets having spring means in surrounding relationship to said arms for urging said arms against an inserted pin.

19. Electrical connecting means as set forth in claim 18 including an insulating housing, said connecting means being contained in said housing.

20. Electrical connecting means comprising a plurality of contact sockets arranged in first and second rows, the sockets of said rows being in side-by-side, parallel, spaced-apart, relationship, said connecting means comprising:

first and second bus strips of conductive metal, said first strip being relatively wider than said second strip, said second strip being against said first strip and extending medially therealong,

each of said sockets comprising four contact arms, two of said arms extending from one side of said first bus strip and two of said arms extending from the one side of said second bus strip which is proximate to said one side of said first bus strip, said arms on said bus strips being in alignment with each other, each of said arms having a twisted portion intermediate its ends and being twisted, at said twisted portion, with respect to its own longitudinal axis thereby to orient an intermediate surface portion of each arm in facing relationship to the axis of said socket, said intermediate surface portion being adapted to be engaged by an inserted contact pin to establish electrical contact therewith, each of said anns extending from its twisted portion generally obliquely towards its respective bus strip, and

each of said sockets having spring means in surrounding relationship to said arms for urging said arms against an inserted pin.

21. Electrical connecting means as set forth in claim 20 including an insulating housing, said connecting means being contained in said housing.

22. Electrical connecting means comprising a plurality of contact sockets arranged as axially aligned spaced-apart pairs of sockets, said connecting means comprising:

first and second bus strips of conductive metal, said strips being substantially identical to each other and being disposed against each other in parallel spaced-apart planes,

each of said sockets comprising four contact arms, two of said arms extending laterally from one side of said first bus strip and two of said arms extending laterally from one side of said second bus strip, said sides being adjacent to each other, said arms on said bus strips being in alignment with each other, each of said arms having a twisted portion intermediate its ends and being twisted, at said twisted portion, with respect to its own longitudinal axis thereby to orient an intermediate surface portion of each arm in facing relationship to the axis of said socket, said intermediate surface portion being adapted to be engaged by an inserted contact pin to establish electrical contact therewith, each of said arms extending from its twisted portion obliquely with respect to said axis thence substantially normally of said planes of said parallel planes to said bus strips, and

each of said sockets having spring means in surroundi g 23. Electrical connecting means as set forth in claim 22 inrelationship to said arms for urging said arm ain t an cluding an insulating housing, said connecting means being inserted pin. contained in said housing.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,605,078 Dated September 1b,, 1971 Inventor) Clarence Leoard Paullus It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 8 was printed incomplete and should read as follows:

" A contact socket as set forth in claim 6 wherein said first and and second strips are substantially identical and are disposed against each other in parallel planes, the axes of said. sockets being parallel to the planes of said strips, said socket and additional socket extending laterally beyond the sides of said strips.

Signed and sealed this 11 th day of March 1972.

(SEAL) Attest:

EUNARD M.FLETCHER,JR. ROBERT GO'I'TSCHALK Attesting Officer Commissioner of Patents 

1. A stamped and formed electrical contact socket adapted to receive a contact pin, said socket comprising at least four contact arms arranged in parallel surrounding relationship to the axis of said socket, said arms having free ends and fixed ends, said free ends defining the entrance to said socket and said fixed ends defining the inner end of said socket, said fixed ends being integral with, and extending from sheet metal strip means, said arms having twisted portions at locations intermediate their ends, said arms being twisted, at said twisted portions, about their own longitudinal axes thereby to orient intermediate surface portions of said arms in facing relationship to said axis of said socket, said intermediate surface portions being adapted to be engaged by an inserted contact pin and to establish electrical contact therewith.
 2. A contact socket as set forth in claim 1 including spring means in surrounding relationship to said arms for urging said arms against said inserted pin.
 3. A contact socket as set forth in claim 1 wherein said strip means extends substantially normally of said axis of said socket, said arms extending from opposite sides of said strip means and being bent adjacent to their fixed ends in a common direction.
 4. A contact socket as set forth in claim 3 wherein said strip means extends laterally beyond said socket and including an additional socket identical to said socket, said additional socket comprising arms integral with, and extending from, said strip means.
 5. A contact socket as set forth in claim 3 wherein said arms extend obliquely from said twisted portions towards said strip means.
 6. A contact socket as set forth in claim 1 wherein said strip means comprises first and second separate strips extending substantially normally of said axis of said socket, two of said arms extending from one side of said first strip and two of said arms extending from one side of said second strip, and including an additional contact socket having arms extending from the remaining sides of said first and second strips.
 7. A contact socket as set forth in claim 6 wherein said second strip extends medially along said first strip.
 8. A contact socket as set forth in claim 6 wherein said first and second strips are suBstantially identical and are disposed against each other in parallel planes, the axes of said sockets being parallel to the
 9. Electrical connecting means comprising at least two contact socket means, each of said socket means being adapted to receive a contact pin, said connecting means comprising: first and second stamped and formed bus sections, each of said bus sections comprising a flat strip of conductive metal, said strips being disposed against each other in parallel planes, each of said contact socket means comprising first and second contact arm means, each said contact arm means having a free end and a fixed end, said fixed end of said first contact arm means of each of said contact socket means being integral with said first bus section and said fixed end of said second contact arm means of each of said contact socket means being integral with said second bus section, said first contact arm means of said first bus section being opposed to said first contact arm means of said second bus section to define at least one said socket means, and said second contact arm means of said first bus section being opposed to said second contact arm means of said second bus section to define at least another one of said contact socket means.
 10. Connecting means as set forth in claim 9 wherein said first and second contact arm means each comprises a pair of contact arms.
 11. Connecting means as set forth in claim 9 comprising pairs of socket means in axial alignment with each other.
 12. Connecting means as set forth in claim 11 wherein said first and second bus sections are of substantially equal width and are against each other in substantially coinciding relationship, said socket means extending in opposite directions from opposite edges of said bus sections.
 13. Connecting means as set forth in claim 9 in which said socket means are axially offset from each other.
 14. Connecting means as set forth in claim 13 wherein said socket means are disposed on parallel spaced-apart axes.
 15. Connecting means as set forth in claim 14 wherein said first bus section has a width which is substantially greater than the width of said second bus section, said second bus section being centrally disposed on said first bus section, said socket means extending from said bus sections in the same direction.
 16. Connecting means as set forth in claim 9 wherein said first and second contact arm means each comprises a plurality of arms extending from said first and second bus sections respectively, said arms in each of said socket means being arranged in a circular array around the socket axis.
 17. Connecting means as set forth in claim 16 including spring means in surrounding relationship to each of said pluralities of arms.
 18. Electrical connecting means comprising a plurality of contact sockets disposed in single file, side-by-side, spaced-apart, parallel relationship, said connecting means comprising: an elongated bus strip of conductive metal, each of said sockets comprising four contact arms, two of said arms being integral with, and extending from, one side of said bus strip and two of said arms being integral with, and extending from, the other side of said bus strip, said arms being in alignment with each other on opposite sides of said strip, each of said arms having a twisted portion intermediate its ends and being twisted, at said twisted portion, with respect to its own longitudinal axis thereby to orient an intermediate surface portion of each arm in facing relationship to the axis of said socket, said intermediate surface portion being adapted to be engaged by an inserted contact pin to establish electrical contact therewith, each of said arms extending from its twisted portion generally obliquely towards said bus strip, and each of said sockets having spring means in surrounding relationship to said arms for urging said arms against an inserted pin.
 19. Electrical connecting means as set forth in claim 18 including an insulating housing, said connecting means being contained in said housing.
 20. Electrical connecting means comprising a plurality of contact sockets arranged in first and second rows, the sockets of said rows being in side-by-side, parallel, spaced-apart, relationship, said connecting means comprising: first and second bus strips of conductive metal, said first strip being relatively wider than said second strip, said second strip being against said first strip and extending medially therealong, each of said sockets comprising four contact arms, two of said arms extending from one side of said first bus strip and two of said arms extending from the one side of said second bus strip which is proximate to said one side of said first bus strip, said arms on said bus strips being in alignment with each other, each of said arms having a twisted portion intermediate its ends and being twisted, at said twisted portion, with respect to its own longitudinal axis thereby to orient an intermediate surface portion of each arm in facing relationship to the axis of said socket, said intermediate surface portion being adapted to be engaged by an inserted contact pin to establish electrical contact therewith, each of said arms extending from its twisted portion generally obliquely towards its respective bus strip, and each of said sockets having spring means in surrounding relationship to said arms for urging said arms against an inserted pin.
 21. Electrical connecting means as set forth in claim 20 including an insulating housing, said connecting means being contained in said housing.
 22. Electrical connecting means comprising a plurality of contact sockets arranged as axially aligned spaced-apart pairs of sockets, said connecting means comprising: first and second bus strips of conductive metal, said strips being substantially identical to each other and being disposed against each other in parallel spaced-apart planes, each of said sockets comprising four contact arms, two of said arms extending laterally from one side of said first bus strip and two of said arms extending laterally from one side of said second bus strip, said sides being adjacent to each other, said arms on said bus strips being in alignment with each other, each of said arms having a twisted portion intermediate its ends and being twisted, at said twisted portion, with respect to its own longitudinal axis thereby to orient an intermediate surface portion of each arm in facing relationship to the axis of said socket, said intermediate surface portion being adapted to be engaged by an inserted contact pin to establish electrical contact therewith, each of said arms extending from its twisted portion obliquely with respect to said axis thence substantially normally of said planes of said parallel planes to said bus strips, and each of said sockets having spring means in surrounding relationship to said arms for urging said arms against an inserted pin.
 23. Electrical connecting means as set forth in claim 22 including an insulating housing, said connecting means being contained in said housing. 